same specs as u do....P4 3.0E @ 3.2Ghz = temp is 43-55*C (idle to load)
mobo is ASUS P4P800-E Deluxe = temp is 35*C - 38*C
RPM of fan = 3500 to 4300RPM (medium speed)
am using Thermaltake Spark 7+ Xaser Edition as my CPU Cooler with Arctic Silver 5 thermal paste..
probably cleaning ur heatsink and fan plus a good thermal paste will do the job.